The invention relates to the art of cooking and particularly apparatus for so called deep fat frying where the comestibles are immersed in a heated cooking oil to effect cooking. Such apparatus, as contemplated herein, is most suited for use in restaurants, institutions and the like where a large volume of comestibles, usually retained before cooking in a frozen condition, are deep fat fried during a relatively short period.
The prior art proposes a variety of fryers intended for large volume cooking of comestibles by deep fat frying techniques. They include equipment where the oil is withdrawn from the pot in which the comestibles are cooked, reheated and then returned to the pot in a continuous circulation procedure during the cooking process. High volume deep fat fryers of the prior art encountered difficulty in avoiding a substantial drop in cooking oil temperature and require excessive time for the oil to regain its desired cooking temperature when a substantial volume of frozen comestibles are introduced into the cooking pot. Ideally, the cooking oil temperature would not only remain at a near constant temperature throughout the cooking process but also the oil temperature should be uniform throughout all portions of the cooking pot during cooking.
It is also desirable for cooking apparatus employing heated cooking oil to have the capability of employing a variety of different cooking oils including those that are in a liquid state at normal room temperature and those that are in a solid state at such normal room temperature. Many of the prior art proposals do not have this capability, particularly those wherein rapid temperature recovery and substantially constant temperature control during the cooking process is maintained by withdrawing the oil from the cooking pot to a rapid input heating unit and then returning it to the cooking pot. Where a solid cooking oil at normal room temperature is employed, the cool down of the oil during non-use of the cooking apparatus involves hardening of the oil throughout the normal cooking oil circulating circuit making start up of the cooking apparatus extremely difficult with this hardened solid cooking oil in the circuit.
It is a principal object of this invention to provide apparatus for deep fat frying comestibles wherein rapid recovery and temperature maintenance of the cooking oil temperature is achieved with a dual capability temperature control, one enabling maintenance of the temperature at the desired adjustable cooking level selected within a variable temperature range and the other providing a fixed standby low temperature which is above normal room temperature and thus maintains the cooking oil at a minimal temperature during extended non-use periods of the cooking apparatus.
A further important object of the invention is to provide cooking apparatus wherein a cooking oil that is normally solid at room temperature can be maintained in a cooking oil circulating type deep fat fryer at a minimal temperature during non-use of the apparatus, such as during an overnight closed down period of the restaurant or institution in which the cooking apparatus is employed.
A further significant object of the instant invention is to provide deep fat frying apparatus wherein a thermistor probe is employed to sense and control the temperature of the cooking oil being withdrawn from the cooking pot to a rapid recovery heating unit and then returned to the pot in a continuous circulation procedure, the thermistor probe being connected with a control unit which has a dual control capability, one to turn the heating source on and off to maintain the desired high cooking temperature within a variable range for temperature selection, and the other to override the variable temperature range control and maintain a relatively low temperature level so that the cooking oil is kept in a liquid state if it be a normally solid cooking oil at room temperature or keep the cooking oil, be it liquid or solid, at a reasonably low start up temperature to expedite start up of the cooking apparatus after an extended shutdown or standby period.
Other objects and advantages of this invention will become apparent from the following description of specific embodiments of the invention taken in connection with the accompanying drawings, the embodiments of this invention being set forth solely by way of illustration and example.